Executions: a new partial-order semantics of Petri nets

Abstract

Executions, a new partial-order semantics of P/T nets, are defined as a generalization of the processes of safe nets. Various relations between executions and processes are established; especially, it is shown that for each net N there is a safe net SN( N) such that the processes of SN( N) are isomorphic to the executions of N. Furthermore, executions are related to other partial-order semantics of nets in much the same way as processes of safe nets are. It is shown that nets are conflict-free (in some sense) if and only if they have just one maximal execution.